Prevalence and clinical manifestations of disseminated Mycobacterium avium complex infection in South Africans with acquired immunodeficiency syndrome

Characterisation and antimicrobial susceptibility pattern of non-tuberculous mycobacteria

Background

Non-tuberculous mycobacteria (NTM) management comprises prolonged therapy that includes macrolides. Non-tuberculous mycobacteria can cause disease in patients with predisposing conditions such as HIV and structural lung disease. Local data on NTM disease and macrolide resistance are scarce, and routine antimicrobial susceptibility testing is currently not performed for NTM in South Africa.

Objectives

This study aims to characterise NTM isolated at Tshepong National Health Laboratory Service (NHLS) according to species and antimicrobial susceptibility pattern.

Method

A retrospective data analysis of NTM isolates from Tshepong NHLS was performed from January to June 2020. GenoType® NTM-DR was performed on selected isolates where the assay can confirm the species and determine resistance to macrolides and aminoglycosides.

Results

Of the 194 collected NTM isolates, 183 were included in the study. Patients' ages ranged from 1 day to 81 years (median 36 years). The most common specimen was sputum (84.7%), followed by gastric aspirate (6.6%). The most common NTM isolated were Mycobacterium (M.) intracellulare (67.6%), M. fortuitum (12.6%), M. species (4.3%), M. kansasii (3.9%), and M. scrofulaceum (3.9%). Macrolide resistance occurred in 2.8% of tested isolates; no aminoglycoside resistance was detected. Although most isolates were from males (62.3%), resistance was observed only in females.

Conclusion

M. intracellulare predominated, with only two M. intracellulare and two M. abscessus isolates showing macrolide resistance; aminoglycoside resistance was absent.

Contribution

This study highlights the need for increased awareness of NTM, regular nationwide NTM surveillance, and monitoring of resistance trends to guide future patient management and ensure good treatment outcomes.

Non-tuberculous mycobacteria pulmonary disease: A review of trends, risk factors, diagnosis and management

Non-tuberculous mycobacteria (NTM) reports have been on the rise globally, with increasing incidence and prevalence accompanied by poor outcomes. The rise has been attributed to an ageing population with increasing comorbid illnesses, and improved laboratory techniques in diagnosing the disease. However, despite the increase, some parts of the world still lack data, especially sub-Saharan African countries. The lack of data in our setting is difficult to explain, as we have a significant burden of NTM risk factors (i.e. HIV, tuberculosis and bronchiectasis). This review therefore serves as a reminder and a challenge to start searching, and reporting on our experiences. The review will highlight the rising incidence, important risk factors, diagnosis and management of NTM pulmonary disease.

Does Disseminated Nontuberculous Mycobacterial Disease Cause False-Positive Determine TB-LAM Lateral Flow Assay Results? A Retrospective Review

We retrospectively reviewed the Determine TB-LAM lateral flow assay (LF-LAM) results among human immunodeficiency virus-infected patients with disseminated nontuberculous mycobacterial (NTM) disease. LF-LAM was positive in 19 of 21 patients without evidence of tuberculosis (TB) coinfection. Although TB-NTM coinfection may have been underdiagnosed, our results suggest that disseminated NTM disease may cause false-positive LF-LAM results.

Mycobacterium avium complex infection in patients with human immunodeficiency virus: A systematic review and meta-analysis

BACKGROUND

Mycobacterium avium-intracellulare complex (MAC) is one of the leading causes of death among people living with human immunodeficiency virus (HIV). The current study was aimed to determine the frequency of MAC infection in patients infected with HIV.

METHODS

Embase, PubMed, and Web of Science were searched for relevant studies. All statistical analyses were performed by STATA version 14.

RESULTS

From 6,627 retrieved articles, 23 were included in the final analysis. A total of 18,463 patients with HIV were included in the analysis. The frequency of MAC infection in patients with HIV was found to be 10.6% (95% confidence interval, 6.9-14.2).

CONCLUSION

The relatively large fractions of HIV-infected patients were coinfected with MAC, which may poses significant public health problems. Continued progress in the development of rapid diagnostic methods and preventive therapy for MAC should lead to further improvements in survival and quality of life in patients with HIV.

Clinical Relevance of Nontuberculous Mycobacteria Isolated from Sputum in a Gold Mining Workforce in South Africa: An Observational, Clinical Study

Background. The clinical relevance of nontuberculous mycobacteria (NTM), detected by liquid more than solid culture in sputum specimens from a South African mining workforce, is uncertain. We aimed to describe the current spectrum and relevance of NTM in this population. Methods. An observational study including individuals with sputum NTM isolates, recruited at workforce tuberculosis screening and routine clinics. Symptom questionnaires were administered at the time of sputum collection and clinical records and chest radiographs reviewed retrospectively. Results. Of 232 individuals included (228 (98%) male, median age 44 years), M. gordonae (60 individuals), M. kansasii (50), and M. avium complex (MAC: 38) were the commonest species. Of 38 MAC isolates, only 2 (5.3%) were from smear-positive sputum specimens and 30/38 grew in liquid but not solid culture. MAC was especially prevalent among symptomatic, HIV-positive individuals. HIV prevalence was high: 57/74 (77%) among those tested. No differences were found in probability of death or medical separation by NTM species. Conclusions. M. gordonae, M. kansasii, and MAC were the commonest NTM among miners with suspected tuberculosis, with most MAC from smear-negative specimens in liquid culture only. HIV testing and identification of key pathogenic NTM in this setting are essential to ensure optimal treatment.

Nontuberculous mycobacteria immune reconstitution syndrome

The prevalence of nontuberculous mycobacteria infection (NTM) in Sub-Saharan Africa is estimated to be less than 1%. NTM is often underdiagnosed or misdiagnosed as tuberculosis in patients who present with immune reconstitution syndrome (IRS) following initiation of antiretroviral treatment (ART). Immune reconstitution syndrome is common in patients who start ART with low CD4 counts and high HIV viral load. Furthermore, Mycobacterium avium complex (MAC) commonly infects those with CD4 counts less than 50 cells/mm³. Three patients, with low baseline CD4 counts, presenting with NTM following the initiation of antiretroviral treatment are described in this case series. The first patient presented with disseminated NTM two weeks after commencing antiretroviral treatment. Acid fast bacilli were found in the liver, duodenum, and bone marrow and were suggestive of MAC microscopically. The second developed cervical lymphadenitis following the initiation of ART. Lymph node aspirate culture grew NTM. The last patient developed pancytopenia after 3 months of ART. AFB was seen on bone marrow biopsy. Culture of the bone marrow aspirate was suggestive of NTM. All three patients improved on ethambutol, clarithromycin, and rifampicin. NTM may be underdiagnosed in areas with a high TB prevalence and should be actively excluded by culture.

Interventions for the prevention of mycobacterium avium complex in adults and children with HIV

BACKGROUND

Mycobacterium avium complex (MAC) infection is a common complication of advanced acquired immunodeficiency syndrome (AIDS) disease and is an independent predictor of mortality and shortened survival.

OBJECTIVES

To determine the effectiveness and safety of interventions aimed at preventing MAC infection in adults and children with HIV infection.

SEARCH METHODS

We searched MEDLINE, EMBASE, and The Cochrane Library (search date December 2012).

SELECTION CRITERIA

Randomised controlled trials comparing different strategies for preventing MAC infection in HIV-infected individuals.

DATA COLLECTION AND ANALYSIS

Two reviewers independently assessed trial eligibility and quality, and extracted data. Where data were incomplete or unclear, a third reviewer resolved conflicts and/or trial authors were contacted for further details. Development of MAC infection and survival were compared using risk ratios (RR) and 95% confidence intervals (CI). The quality of evidence has been assessed using the GRADE methodology.

MAIN RESULTS

Eight studies met the inclusion criteria. Placebo-controlled trials: There was no statistically significant difference between clofazimine and no treatment groups in the number of patients that developed MAC infection (RR 1.01; 95% CI 0.37 to 2.80). Rifabutin (one study; RR 0.48; 95% CI 0.35 to 0.67), azithromycin (three studies; RR 0.37; 95% CI 0.19 to 0.74) and clarithromycin (one study; RR 0.35; 95% CI 0.21 to 0.58) were more effective than placebo in preventing the development of MAC infection. There was no statistically significant difference between those treated with clofazimine (one study; RR 0.98; 95% CI 0.41 to 2.32), rifabutin (one study RR 0.91; 95% CI 0.78 to 1.05), azithromycin (three studies, pooled RR 0.96; 95% CI 0.69 to 1.32) and placebo in number of reported deaths. One study found that the risk of death was reduced by 22% in patients treated with clarithromycin compared to those treated with placebo (RR 0.78; 95% CI 0.64 to 0.96). Monotherapy vs. monotherapy: Patients treated with clarithromycin (RR 0.60; 95% CI 0.41 to 0.89) and azithromycin (RR 0.60; 95% CI 0.40 to 0.89) were 40% less likely to develop MAC infection than those treated with rifabutin. There was no statistically significant difference between those treated with clarithromycin (RR 0.98; 95% CI 0.83 to 1.15), azithromycin (RR 0.98; 95% CI 0.77 to 1.24) and rifabutin in the number of reported deaths. Combination therapy versus monotherapy: There was no statistically significant difference between patients treated with a combination of rifabutin and clarithromycin and those treated with clarithromycin alone (RR 0.74; 95% CI 0.46 to 1.20); and those treated with combination of rifabutin and azithromycin and those treated with azithromycin alone (RR 0.59; 95% CI 1.03). Patients treated with a combination of rifabutin plus clarithromycin were 56% less likely to develop MAC infection than those treated with rifabutin alone (RR 0.44; 95% CI 0.29 to 0.69). Patients treated with a combination of rifabutin plus azithromycin were 65% less likely to develop MAC infection than those treated with rifabutin alone (RR 0.35; 95% CI 0.21 to 0.59). There was no statistically significant difference in the number of reported deaths in all the four different comparisons of prophylactic agents.

AUTHORS' CONCLUSIONS

Based on limited data, azithromycin or clarithromycin appeared to be a prophylactic agent of choice for MAC infection. Further studies are needed, especially direct comparison of clarithromycin and azithromycin. In additions, studies that will compare different doses and regimens are needed.

The role of speciation in positive Lowenstein-Jensen culture isolates from a high tuberculosis burden country

Objective

To determine the need for routine speciation of positive Lowenstein-Jensen mycobacterial cultures in HIV-infected patients suspected of having pulmonary tuberculosis at Mulago Hospital in Kampala, Uganda.

Methods

Sputum and bronchoalveolar lavage Lowenstein-Jensen mycobacterial culture isolates from consecutive, HIV-infected patients admitted to Mulago Hospital with 2 weeks or more of cough were subjected to IS6110 PCR and rpoB genetic analysis to determine the presence of Mycobacterium tuberculosis complex (MTBC) and non-tuberculous mycobacteria (NTM).

Results

Eighty (100%) mycobacterial cultures from 65 patients were confirmed to be members of MTBC. Subsequent analysis of the cultures from 54 patients by PCR and sequence analyses to identify co-infection with NTM confirmed the presence of MTBC as well as the presence of Micrococcus luteus (n = 4), Janibacter spp. (n = 1) and six cultures had organisms that could not be identified.

Conclusions

Presumptive diagnosis of tuberculosis on the basis of a positive Lowenstein-Jensen culture is sufficient in HIV-infected Ugandans suspected of having tuberculosis. Routine molecular confirmation of positive Lowenstein-Jensen cultures is unnecessary in this low resource setting.

Clinical relevance of nontuberculous Mycobacteria, Oman

Little is known about the clinical relevance of nontuberculous mycobacteria (NTM) in the Arabian Peninsula. We assessed the prevalence and studied a random sample of isolates at a reference laboratory in Muscat, Oman. NTM cause disease in this region, and their prevalence has increased.

[Clinical manifestations of HIV infection in distinct geographical areas]

The clinical manifestations of HIV infection vary widely in distinct geographical areas. While HIV-related disease has been well characterized in western countries, relatively few publications have described the clinical manifestations of these diseases in tropical areas, where the vast majority of HIV-infected people are concentrated. In addition, HIV infection may alter the natural history of tropical diseases in several ways and tropical diseases influence the course of HIV infection. The present review describes the major opportunistic infections afflicting people with HIV/AIDS in Africa, Latin America, and Asia and discusses the mutual interactions between HIV and the major tropical diseases.

Causes of death in hospitalized adults with a premortem diagnosis of tuberculosis: an autopsy study

OBJECTIVE

To ascertain the immediate and underlying causes of death in adults who died in hospital with a premortem diagnosis of tuberculosis.

DESIGN

Causes of death were assessed independently by internists and pathologists in 50 adults admitted to two Soweto hospitals who died 24 h or more after admission. Detailed record reviews and complete autopsies, including HIV tests when not performed premortem, were performed. In addition, a variety of postmortem microbiological tests were performed.

RESULTS

Forty-seven patients had HIV infection; all were antiretroviral naive. Their median age was 34.5 years, median CD4 cell count was 48 cells/microl and median length of hospitalization before death was 6 days. Autopsy confirmed the premortem diagnosis of tuberculosis in 37 HIV-infected patients (79%), whereas 10 (21%) did not demonstrate tuberculosis. Bronchopneumonia and cytomegalovirus pneumonitis were the leading pathologies in these 10 patients. In 47 HIV-infected cadavers immediate or contributory causes of death were: extensive pulmonary tuberculosis, 32 (68%); disseminated tuberculosis, 28 (60%); bacterial pneumonia, 13 (26%); cytomegalovirus pneumonitis in seven (15%); cytomegalovirus DNA was found in 31 (66%) and Pneumocystis pneumonia was found in five cadavers (11%). The lung, followed by lymph nodes, liver and kidney, were the commonest sites of tuberculosis. Mycobacterium tuberculosis was cultured from 19 spleens, one of which was multidrug resistant, and Salmonella spp. was cultured from 11 splenic specimens.

CONCLUSION

We demonstrated disseminated, extensive tuberculosis associated with advanced HIV disease. Severe bacterial infections, including salmonellosis, were the leading co-morbidity, suggesting that hospitalized HIV-infected adults in whom tuberculosis is suspected may benefit from broad-spectrum antibiotic therapy.

High incidence of atypical mycobacteriosis in African HIV-infected adults with low CD4 cell counts: a 6-year cohort study in Côte d'Ivoire

The role of non-tuberculous mycobacteriosis (NTM) in HIV-related diseases in sub-Saharan Africa has long been controversial. In a 6-year cohort of 721 HIV-infected adults with systematic BACTEC blood cultures in Abidjan, Côte d'Ivoire, the incidence of NTM was 1.8/100 person-years overall and 12.2/100 person-years in patients with baseline CD4 cell counts < 100 cells/mm3. In sub-Saharan Africa, where most patients start highly active antiretroviral therapy with low CD4 cell counts, improving the diagnosis of NTM may be relevant.

Disseminated mycobacterium avium-intracellulare complex (MAC) infection in the era of effective antiretroviral therapy: is prophylaxis still indicated?

Before highly active antiretroviral therapies (HAART) were available for the treatment of persons with HIV infection, disseminated Mycobacterium avium-intracellulare complex (MAC) infection was one of the most common opportunistic infections that affected people living with AIDS. Routine use of chemoprophylaxis with a macrolide has been advocated in guidelines for the treatment of HIV-infected individuals if they have a circulating CD4+ cell count of < or =50 cells/microL. In addition, lifelong prophylaxis for disease recurrence has been recommended for those with a history of disseminated MAC infection. The introduction of HAART has resulted in a remarkable decline in the incidence of opportunistic infections and death among persons living with AIDS. Considerable reconstitution of functional immune responses against opportunistic infections can be achieved with HAART. In the case of infection with MAC, there has been a substantial reduction in the incidence of disseminated infections in the HAART era, even in countries where the use of MAC prophylaxis was never widely accepted. Moreover, the clinical picture of MAC infections in patients treated with potent antiretroviral therapies has shifted from a disseminated disease with bacteraemia to a localised infection, presenting most often with lymphadenopathy and osteomyelitis. Data from several recently conducted randomised, double-blind, placebo-controlled trials led to the current practice of discontinuing primary and secondary prophylaxis against disseminated MAC infections at stable CD4+ cell counts >100 cells/microL. These recommendations are still conservative as primary or secondary disseminated MAC infections are only rarely seen in patients who respond to HAART, despite treatment initiation at very low CD4+ cell counts. Potential adverse effects of macrolide therapy and drug interactions with antiretrovirals also metabolised via the cytochrome P450 enzyme system must be critically weighed against the marginal benefit that MAC prophylaxis may provide in addition to treatment with HAART. These authors feel that, unless patients who initiate HAART at low CD4+ cell counts do not respond to HIV-treatment, routine MAC prophylaxis should not be recommended. Nevertheless, the patient population for whom MAC prophylaxis may still be indicated in the era of HAART needs to be identified in prospectively designed clinical trials.